Developer apparatus

ABSTRACT

Means detect positioning of a medium bearing a latent image and responsive thereto actuate discharge of developer material from hopper means. Means convey the medium and developer material thereon about a heated drum. Endless belt means conform the medium to the drum.

[ Aug.6,1974

United States Patent 11 1 Takahashi et al.

ATIONS 3,168,022 2/1965 Limberger 0 s 3,374,769 3/1968 01116611.... 3,411,932 11/1968 Malone C131... both of Tokyo, Japan 3,526,191 9/1970 SllVCrbCrg et a1... 3,572,555 3/1971 Knight 61 al. Rmh 3,716,018 2/1973 Ohm 61 a1. FOREIGN PATENTS OR APPLIC DEVELOPER APPARATUS [75] Inventors: Yasuhiro Takahashi;

[73] Assignee: Tokyo, Japan [22] Filed: Feb. 11, 1972 a uh" .1" 6

a wn Ta GC 73 005 009 H 34 72 200 42 9 4 o N m.

[30] Foreign Application Priority Data Feb. 15, 1971 July 16, 1971 46-8216 Primary Examiner Morris p a 46-63344 Attorney, Agent, or FirmCooper, Dunham, Clark, Griffin & Moran ABSTRACT Means detect positioning of a medium bearing a latent Int. [58] Field of Search...........

image and responsive thereto actuate discharge of developer material from hopper means. Means convey [56] References Cited the medium and developer material thereon about a UNITED STATES PATENTS heated drum. Endless belt means conform the medium to the drum.

3,110,612 11/1963 Gottwald et a1. 118/60 X 3,128,379 4/1964 Cisek et a1. 118/637 UX 4 Claims, 4 Drawing Flgures PArzmwm sum 3. 827394 SHEET 1 OF 2 PAKNIEWB s m SHEET 2 OF 2 FIG.3

1 DEVELOPER APPARATUS i BACKGROUND OF THE INVENTION This invention relates to a developing device using a powder developing agent for developing exposed binary system photosensitive sheets of the diazo type.

The use of a developing agent comprising silica or glass beads in minute powder form moist with an alkaline developing liquid, such for example as an organic amine, for developing binary system photosensitive sheets of the diazo type after such photosensitive sheets have been exposed to an optical image of an original offers many advantages. The duplicates made by using this developing agent are free from odor which tends to render the duplicates made by using ammonia rather objectionable. The developed photosensitive sheets are not discharged from the copying machine in wet condition which is the case when the photosensitive sheets are developed with a liquid developing agent. The use of the developing agent described above permits duplicates of good tone and contrast to bemade and provided in dry condition.

SUMMARY OF THE INVENTION This invention has as its object the provision of a developing device adapted to carry into practice what is called a powder developing method which permits a numer of discrete exposed photosensitive sheets to be developed successively, continuously and positively, and which minimizes the waste of the developing agent.

The developing device according to this invention offers many advantages. The waste of the developing agent is minimized, so that the prolonged use of the powder permits the cost for developing to be greatly reduced. Since photosensitive sheets can be delivered continuously to the developing device, they can be developed continuously and positively.

According to this invention, a small gap is provided between the outlet port of the powder containing vessel and the guide plate for photosensitivesheets, so that the supply of powder from the vessel is automatically interrupted by the automatic port closing action of the powder when no photosensitive sheet moves through the gap but a uniform quantity of the powder is supplied to the photosensitive sheet when it is moved through the gap below the outlet port. The quantity of the powder used for each photosensitive sheet may vary depending on the size of the particular photosensitive sheet and will be minimized, thereby permitting developing to be carried out at high efficiency in spite of the fact that the device is simple in constuction If the outlet port of the vessel is of slit shape and disposed parallel to and across the width of photosensitive sheets, the developing device will permit a plurality of exposed photosensitive sheets to be developed simultaneously as they move in side-by-side relationship while yet offering the aforementioned advantages.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of the diazo type photosen- FIG. 3 and 4 are sectional views showing other forms of the developing agent supply means of the developing device according to this invention.

Description of a Preferred Embodiment FIG. [shows one embodiment of the diazo type photosensitive sheet developing device according to this invention, in which an endless belt 6 trained about belt rollers 2, 3, 4 and 5 is shown as being maintained in pressing engagement with a left half portion of an outer peripheral surface of a rotary cylinder 1 for a circumferential extent of the order of over Roller 2 of all the belt rollers is disposed rightwardly downwardly of cylinder 1 in the figure. Disposed above roller 2 or rightwardly of cylinder 1 is a vessel 7 supported by support shafts 8, 9 and 10. An upper edge 7a of vessel 7 which is disposed adjacent cylinder 1 extends outwardly into engagement with the outer peripheral surface of cylinder 1.

A developing agent 11 comprising minute powder of silica or glass beads moist with alkaline developing liquid, such for example as an organic amine, is contained in vessel 7 which also mounts therein a rotary shaft 12a provided with agitation blades 12. Agitation blades 12 are not essential and may be done without.

Vessel 7 is formed in its bottom with an opening 13 which is blocked by a brush roller 14, mounted within vessel 7 and disposed inwardly of opening 13, when roller 14 remains inoperative. When brush roller 14 rotates, it performs the action of discharging developing agent 11 through opening 13.

The opening 13 formed in the bottom of vessel 7 is disposed above a guide plate 15 mounted rightwardly of roller 2 in FIG. 1 which guide plate has attached thereto an actuator 16a for a microswitch 16. A pair of rollers 17 for conveying exposed photosensitive sheets is mounted rightwardly of guide plate 15 in the figure. Vessel 7 and brush roller 14 constitute developing agent supply means which supplies a quantity of developing agent 11 to the exposed photosensitive surface of each photosensitive sheet when the latter is delivered by the pair of rollers 17 to a position below opening 13. Brush roller 14 begins to rotate when the photosensitive sheet pushes and moves actuator 16a and closes microswitch l6, and rotates while switch 16 remains closed. The photosensitive sheet is moved leftwardly by the pair of rollers 17 in FIG. 1 while the developing agent is applied to its photosensitive layer and it is transferred to endless belt 6. The photosensitive sheet conveyed by endless belt 6 is held between endless belt 6 and cylinder 1 and caused by endless belt 1 to press against the outer peripheral surface of cylinder 1 with a substantial force. Application of pressure to the photosensitive sheet results in the developing agent on its photosensitive surface being brought into intimate contact therewith, so that the alkaline developing liquid is supplied to the photosensitive surface in a quantity sufficiently great to provide a good visible image of the original on the sheet. The photosensitive sheet is of the so-called diazo type having a binary system photosensitive layer which consists of a mixture of a diazonium salt and a coupler and disposed on a photosensitive layer supporter or base made of paper or a synthetic resin sheet.

Heating means 18 comprising infrared ray lamps or nichrome wires is mounted in the interior of cylinder 1. Each exposed photosensitive sheet moved around cylinder 1 by being caused by belt 6 to press against the outer peripheral surface of cylinder 1 is heated while being developed, so as to ensure that the latent image thereon is converted into a visible image.

Disposed rightwarclly of belt roller which in turn is disposed above cylinder 1 in FIG. 1 is a developed photosensitive sheet discharge roller 19, to which is maintained in light pressing engagement a cleaing brush roller adapted to rotate in a direction in which it rubs against roller 19. Disposed below developed photosen sitive sheet discharge roller 19 is a photosensitive sheet stripper 22 consisting of a plurality of stripper plates made of a synthetic resinous material and mounted on a support shaft 21 in side-by-side relationship. Stripper 22 is provided with pawls 22a maintained in engagement with the outer peripheral surface of cylinder 1. Each developed photosensitive sheet is stripped off cylinder 1 by pawls 22a and introduced between two rollers 19 and 20. The photosensitive sheet held between two rollers 19 and 20 has the developing agent adhering to its surface scrapedoff therefrom by brush roller 20 and is discharged from the machine as a duplicate. The developing agent removed from the developed photosensitive sheet drops into vessel 7.

FIG. 2 shows another form of developing agent supply means. A plurality of slits 23 disposed parallel to one another are formed in the bottom of vessel, and an oscillatory plate formed therein with a plurality of slits 24 corresponding to slits 23 is mounted above slits 23 formed in the bottom of vessel 7. Oscillatory plate 25 is reciprocable between two positions; it is moved to a position in which the slits 24 in plate 25 and the slits 23 in vessel 7 are offset so that the latter may be closed when on developing agent is to be supplied, but is is moved in oscillatory motion in the direction of arrows between two positions by drive means connected to a connection 25a when a quantity of developing agent is to be supplied to the exposed photosensitive sheet below vessel 7 so that the developing agent in vessel 7 may be discharged downwardly through slits 23 and 24.

FIG. 3 shows another form of developing agent supply means. Minute powder 119 moist with a developing liquid is contained in a vessel 121 which is removably supported by support shafts 122, 123 and 124 connected to opposite side plates (not shown) of the copying machine. A slit-shaped outlet port 121a arranged across the width of a photosensitive sheet 101 is formed in the bottom of vessel 121 and disposed in close proximity to a guide plate 106 such that a small clearance is defined therebetween. As a result, a uniform quantity of developing agent is discharged through slit-shaped opening 121a on to guide plate 106 at all times and accumulated thereon. The powder itself blocks and closes the opening after a uniform quantity of developing agent has been discharged through it, so as to restrict the quantity of supplied developing agent to an essential minimum.

The exposed photosensitive sheet 101 delivered by a pair of feed rollers 104 and 105 rotating in the direction of arrows 102 and 103 respectively are guided by guide plates 106 and 107 and moved to a position below vessel 121. The leading end of the photosensitive sheet scoops up the quantity of minute powder accuis sprayed with the powder as the sheet moves under vessel 121.

While photosensitive sheet 101 is moving below vessel 121, minute powder 119 is continuously discharged through outlet port 1210 because no powder is accumulated below outlet port 121a, so that the upper surface of photosensitive sheet 101 is sprayed with a uniform quantity of minute powder as it moves below vessel 121. As soon as the trailing end end of photosensitive sheet 101 moves past the bottom of vessel 121, the minute powder discharged through outlet port 121a is accumulated on guide plate 106 till the port is blocked by powder so that a uniform quantity of powder may be piled on the guide plate and no powder may be discharged in excess through outlet port 121a.

The exposed photosensitive sheet 101 having a quantity of powder disposed on its surface is delivered by an endless belt (not shown) and caused thereby to press against the outer peripheral surface of a cylinder 108 so that it may be developed. After being developed, photosensitive sheet 101 is discharged through an outlet not shown) as a duplicate. The powder adhering to the developed photosensitive sheet or duplicate is brushed and returned to vessel 121 by means of a brush (not shown). The powder adhering to cylinder 108 is scraped off by a scrape-off edge 121b of vessel 121 maintained in contact with the outer peripheral surface of cylinder 108 and returned to vessel 121. If this developing agent supply means is used for supplying minute powder 119 to the exposed photosensitive sheet disposed below the vessel, the quantity of minute powder directly concerned in developing may vary depending on the size of the photosensitive sheet, so that the quantity of wasted developing agent can be minimized.

FIG. 4 shows still another form of developing agent supply means which is based on the same principle as the developing agent supply means shown in FIG. 3. The supply means of FIG. 4 is characterized by a powder supply roller 227 mounted in an outlet orifice 2260 of a vessel 226 and adapted to rotate at all times.

The outlet orifice 226a formed in the bottom of vessel 226 is disposed in close proximity to a guide plate 206 such that a small clearance is defined therebetween as is the case with bottom opening 121a and guide plate 106 of FIG. 3. A portion of the outer peripheral surface of the powder supply roller 227 mounted in the outlet orifice 226a of vessel 226 and adapted to rotate about a shaft 228 in the direction of an arrow 229 is exposed. The outer peripheral surface of powder supply roller 227 is formed with a number of elevated portions and depressed portions for facilitating the supply of powder to the photosensitive sheet. If the elevated portions and depressed portions are too great in dimensions, minute powder will be discharged v through the orifice irrespective of whether or not the photosensitive sheet is moving below the vessel and it is not possible to close the orifice by the action of powder itself. However, if an optimum dimension is selected for the elevated portions and depressed portions, minute powder will be supplied in a uniform quantity and the orifice can be closed by the orifice closing action of powder itself after a uniform quantity thereof has been supplied to the photosensitive sheet. Besides, the gap between the outlet orifice and the guide plate can be prevented from being clogged with powder. If the rate of rotation of the powder supply roller is varied in accordance with the rate at which the photosensitive sheet is fed, it will be possible to form on the photosensitive sheet a layer of powder which has a uniform thickness regardless of the rate at which the photosensitive sheet moves.

In the diazo type photosensitive sheet developing device according to this invention in which various forms of developing agent supply means can be used, the photosensitive sheet pressing and conveying means may comprise a pair of soft rollers of relatively large size maintained in pressing engagement with each other, in place of the endless belt and the cylinder as shown and described above. If the rollers used for this purpose are made of electrically conducting rubber, it will be possible to heat the photosensitive sheet held between them by heating the rollers and the heating means can be done without.

What we claim is:

1. A diazo type photosensitive sheet developing device using fine powder moistened with developing fluid as a developing agent, said device comprising:

means for delivering exposed diazo type photosensitive sheets to a developing agent receiving position;

a vessel for containing a quantity of said developing agent;

means for detecting the delivery of an exposed sheet to said receiving position and for providing a detection signal when a sheet is in said receiving position;

developing agent supply means acting in response to a detection signal from the detecting means for supplying to each photosensitive sheet delivered to the receiving position a quantity of the developing agent contained in the vessel;

photosensitive sheet conveying and pressing means for conveying photosensitive sheets, with the developing agent supplied thereto, away from the receiving position and for pressing together the conveyed sheets and the developing agent supplied thereto, said conveying and pressing means comprising a rotatable heated drum and an endless belt pressing against a substantial portion of the circumference of the drum and moving therewith to press together a photosensitive sheet and the developing agents supplied thereto between the endless belt and the drum;

means for stripping sheets from the drum subsequent to the pressing and conveying thereof; and

means for cleaning the stripped sheets of loose developing agent.

2. A diazo type photosensitive sheet developing device as in claim 1 wherein the developing agent supply means include: means defining an opening at the lower end of the vessel, a brush roller positioned in said opening and dimensioned to block the opening, said brush roller rotating responsive to said signal when a photosensitive sheet is at said receiving position, to thereby deliver a quantity of the developing agent from the vessel to the sheet which is at the receiving position.

3. A diazo type photosensitive sheet developing device as in claim 1 wherein the developing agent supply means include:

means defining a plurality of parallel slits in the lower end of the vessel, and an oscillatory plate having a plurality of slits corresponding in size and position to the slits in the vessel, said oscillatory plate having a first position in which its slits are aligned with the slits in the vessel to thereby permit developing agent from the vessel to seep out through said aligned slits and having a second position in which it blocks the slits in the vessel to prevent flow of developing agent out of the vessel, said oscillatory plate moving between its first and second position responsive to said signal when a sheet is at said receiving position to thereby allow developing agent from the vessel to be supplied to the sheet.

4. A diazo type photosensitive sheet developing device as in claim 1 wherein the developing agent supply means include: a developing agent supply roller rotatable about its longitudinal axis and having on its outer periphery a plurality of axially extending grooves, means defining an opening in the lower end of the vessel dimensioned to be blocked by the roller when the roller is stationary, and means for supporting the roller within said opening, said roller rotating responsive to said signal when a sheet is at said receiving position to deliver developing agent out of the vessel and onto the sheet. 

1. A diazo type photosensitive sheet developing device using fine powder moistened with developing fluid as a developing agent, said device comprising: means for delivering exposed diazo type photosensitive sheets to a developing agent receiving position; a vessel for containing a quantity of said developing agent; means for detecting the delivery of an exposed sheet to said receiving position and for providing a detection signal when a sheet is in said receiving position; developing agent supply means acting in response to a detection signal from the detecting means for supplying to each photosensitive sheet delivered to the receiving position a quantity of the developing agent contained in the vessel; photosensitive sheet conveying and pressing means for conveying photosensitive sheets, with the developing agent supplied thereto, away from the receiving position and for pressing together the conveyed sheets and the developing agent supplied thereto, said conveying and pressing means comprising a rotatable heated drum and an endless belt pressing against a substantial portion of the circumference of the drum and moving therewith to press together a photosensitive sheet and the developing agents supplied thereto between the endless belt and the drum; means for stripping sheets from the drum subsequent to the pressing and conveying thereof; and means for cleaning the stripped sheets of loose developing agent.
 2. A diazo type photosensitive sheet developing device as in claim 1 wherein the developing agent supply means include: means defining an opening at the lower end of the vessel, a brush roller positioned in said opening and dimensioned to block the opening, said brush roller rotating responsive to said signal when a photosensitive sheet is at said receiving position, to thereby deliver a quantity of the developing agent from the vessel to the sheet which is at the receiving position.
 3. A diazo type photosensitive sheet developing device as in claim 1 wherein the developing agent supply means include: means defining a plurality of parallel slits in the lower end of the vessel, and an oscillatory plate having a plurality of slits corresponding in size and position to the slits in the vessel, said oscillatory plate having a first position in which its slits are aligned with the slits in the vessel to thereby permit developing agent from the vessel to seep out through said aligned slits and having a second position in which it blocks the slits in the vessel to prevent flow of developing agent out of the vessel, said oscillatory plate moving between its first and second position responsive to said signal when a sheet is at said receiving position to thereby allow developing agent from the vessel to be supplied to the sheet.
 4. A diazo type photosensitive sheet developing device as in claim 1 wherein the developing agent supply means include: a developing agent supply roller rotatable about its longitudinal axis and having on its outer periphery a plurality of axially extending grooves, means defining an opening in the lower end of the vessel dimensioned to be blocked by the roller when the roller is stationary, and means for supporting the roller within said opening, said roller rotating responsive to said signal when a sheet is at said receiving position to deliver developing agent out of the vessel and onto the sheet. 